Secure TeamChat

This is a Python project that implements a secure team chat application suitable for cross-platform usage.

Features

• Cross-Platform: Runs on both Windows and POSIX/Linux devices.
• GUI on Windows: The application uses Python's built-in tkinter library to provide a graphical user interface (GUI) for Windows users.
• Terminal Chat on POSIX/Linux: On POSIX/Linux devices, the chat is run through the terminal.
• Password-based Authentication & Encryption:
  • Users agree on a session password that is set by the session manager (relay).
  • The password is used to authenticate users and encrypt the session key with AES256.
  • The session key is transmitted securely using HMAC PBKDF (Password-Based Key Derivation Function).
  • Each session has its own unique key, ensuring that each session is cryptographically separated and secured.

Requirements

• Python 3.x
• tkinter (for GUI on Windows)
• Libraries for cryptographic operations such as HMAC and PBKDF

Usage

Starting a session

1. Launch the application using the appropriate command for your platform.

   • Windows (GUI): python client.py
   • Linux/Unix (Terminal): python client.py

2. The session manager will ask for a session password. Once agreed upon, users can authenticate and join the session.

3. All communication in the session is encrypted using the unique session key.

How It Works

1. Session Password: Users agree on a password that the session manager sets.
2. Authentication: The password is used to authenticate users.
3. Secure Session Key: The session manager derives a unique session key and transmits it to the users via a secured method (HMAC PBKDF2).
4. Cryptographically Isolated: Each session uses a unique session key, ensuring that data from one session is cryptographically separated from other sessions.
5. Communication: Users communicate securely via AES256 encryption based on the session key.

Security Considerations

• The session key is derived and transmitted securely using HMAC PBKDF2, ensuring strong encryption.
• Only authenticated users are allowed to access the session.
• Each session has a unique session key to protect against unauthorized access or data leaks between sessions.

License

MIT License. See LICENSE for more details.

Contributing

Contributions are welcome! Please fork the repository, create a new branch, and submit a pull request with your changes.